IS0 7-1:1994 pdf download – Pipe threads where pressure-tight joints are made on the threads – Part 1: Dimensions, tolerances and designation
1 Scope This part of IS0 7 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes l/16 to 6 inclusive, for joints made pressure-tight by the mating of the threads. These threads are taper external, parallel internal or taper internal and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipment interconnected by threaded joints. An appropriate jointing medium should be used on the thread to ensure pressure-tight joints. NOTES 1 Parallel external pipe threads are not suitable as jointing threads. 2 For pipe threads where pressure-tight joints are not made on the threads, see IS0 228-l. 3 IS0 7-2 gives details of methods of verification of joint- ing thread dimensions and form and recommended gauging systems. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this part of IS0 7. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of IS0 7 are encouraged to investigate the pos- sibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0
maintain registers of currently valid International Standards. IS0 7-2:1982, Pipe threads where pressure-tight joints are made on the threads – Part 2: Verification by means of limit gauges. 3 Definitions For the purposes of this part of IS0 7, the following definitions apply (see also figures 3 and 5). 3.1 gauge diameter: Major diameter of the thread, whether external or internal. 3.2 major cone: Imaginary cone which just touches the crests of a taper external thread or the roots of a taper internal thread. 3.3 gauge plane: Plane, perpendicular to the axis of the taper thread, at which the major cone has the gauge diameter. NOTE 4 For external threads the gauge plane is located at a distance equal to the nominal gauge length from the small end of the thread. For internal threads the gauge plane is located at a distance of half-pitch behind the face of the threaded part. This is in order to give consideration to the start of the thread that has been removed by chamfering. 3.4 gauge length: On an external thread, the dis- tance from the gauge plane to the small end of the thread.